1. FIELD OF THE INVENTION
The present invention relates to a base manipulation device for an office chair.
2. DESCRIPTION OF THE RELATED PRIOR ART
The closest prior art of which the applicant is aware is disclosed in the Taiwanese Patent Publication No. 297246. In the said patent, the operation rod for operating the pneumatic bar 4 and the push rod 69 for operating the angle of inclination of the seat back are arranged in a separate manner, so that the operation thereof cannot be integrated, thereby causing inconvenience and difficulty in operation. In addition, the inclined angle of the seat back can be adjusted, but the inclined angle of the seat cushion cannot be adjusted, so that the design cannot suit the ergonomic and comfortable requirements.
In accordance with the present invention, there is provided a base manipulation device for an office chair, comprising: a seat cushion having a back face secured with a bottom plate which has a front end pivoted with a front end of a chair base which has a mediate portion mounted with a pneumatic bar, a seat back support rack having a distal end secured with a swing base which has a distal end pivoted with the mediate portion of the chair base, the bottom plate having a rear end having two sides each having a slide received in an elongated slot defined in each of two sides of the swing base, the bottom plate having a back face having a rear side secured with a locking portion defining a plurality of locking slots, wherein:
the mediate portion of the chair base has a top face provided with a rotatable rotation plate, the rotation plate is provided with an upright pivot plate and an upright drive plate, an operation bar is pivoted on the pivot plate and has a distal end that can be pressed on a control point of the pneumatic bar, a rod extends through the drive plate, a first elastic member is mounted on the rod and is urged between a first end of the rod and a first side of the drive plate, a second elastic member is mounted on the rod and is urged between a second end of the rod and a second side of the drive plate, a positioning plate is secured on the first end of the rod and is slidable in a space formed by a piece on the chair base;
when the operation bar is driven to pivot up and down, the pneumatic bar is driven to adjust a height of a seat;
when the operation bar is driven to move rightward and leftward, the rotation plate is rotated to move the drive plate which moves the rod which moves the positioning plate to insert into or detach from either one of the locking slots of the locking portion of the bottom plate, thereby achieving a purpose of adjusting an angle of inclination of the seat.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.